Roofing material and method of laying same

ABSTRACT

A shingle unit, a method or system of applying the shingle units to a roof or siding and the roof or siding thus produced. The shingle unit includes rectangular under and over sheets hingedly connected along a common edge for pivotal movement between a face-to-face position and an extended co-planar position with the over sheet and under sheet being longitudinally offset to define an overhang portion of the over sheet and an extension portion of the under sheet. Adjacent shingle units are aligned with the overhang portion of one shingle unit in face-to-face abutting relationship with the extension portion of an adjacent shingle unit to define exposed gaps between the over sheets or adjacent units. The under sheet or each shingle unit is fastened to the underlying supporting surface along the hinged edge while the sheets are in the extended position and the over sheet is then folded to the face-to-face position to cover and conceal the fasteners. The free edges of the over and under sheets lie beneath the shingle units in the next adjacent course or row and are fastened to the underlying surface by the fasteners securing the next adjacent row. A series of successive courses or rows of shingle units are placed and fastened with each successive row having units are placed and fastened with each successive row having the lower edges of the shingle units therein overhanging the upper edges of the units in the previously laid row to cover the entire surface with a double thickness of material.

United States Patent [191 Shearer 1 ROOFING MATERIAL AND METHOD OF LAYING SAME Eugene L. Shearer, Englewood, Colo.

[73] Assignee: Windarama Shingles System, Inc.,

Denver, C010.

[22] Filed: Dec. 17, 1973 [21] Appl. No.: 425,252

[75] Inventor:

Primary E.tuminerPrice C. Faw, Jr. Attorney, Agent, or FirmBurton, Crandell & Polumbus [57] ABSTRACT A shingle unit, a method or system of applying the 1 July 15, 1975 shingle units to a roof or siding and the roof or siding thus produced. The shingle unit includes rectangular under and over sheets hingedly connected along a common edge for pivotal movement between a faceto-face position and an extended co-planar position with the over sheet and under sheet being longitudinally offset to define an overhang portion of the over sheet and an extension portion of the under sheet. Adjacent shingle units are aligned with the overhang portion of one shingle unit in face-to-face abutting relationship with the extension portion of an adjacent shingle unit to define exposed gaps between the over sheets or adjacent units. The under sheet or each shingle unit is fastened to the underlying supporting surface along the hinged edge while the sheets are in the extended position and the over sheet is then folded to the face-to-face position to cover and conceal the fasteners. The free edges of the over and under sheets lie beneath the shingle units in the next adjacent course or row and are fastened to the underlying surface by the fasteners securing the next adjacent row. A series of successive courses or rows of shingle units are placed and fastened with each successive row having units are placed and fastened with each successive row having the lower edges of the shingle units therein overhanging the upper edges of the units in the previously laid row to cover the entire surface with a double thickness of material.

11 Claims, 18 Drawing Figures ROOFING MATERIAL AND METHOD OF LAYING SAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to surfacecovering systems and more particularly relates to a shingle unit, a method of applying same and the surface covering resulting therefrom, the shingle units finding particular but not necessarily exclusive utility for use in the roofing of building structures.

2. Description of the Prior Art Cedar shake shingles have long been one of the more desirable roof covering materials primarily because of their thickness which presents a thick butt or shadow line between courses or rows of shingles. The quality of cedar shake shingles, however, has recently been declining while the price has been rising so that their commercial appeal has somewhat subsided.

The so-called composite shingles which are made of an asphalt material impregnated with crushed mineral grit on one surface has always been more economical to use as roof covering but have not had the thick butt lines presented by cedar shake shingles and for this reason have not provided the attractive appearance demanded by a large segment of the purchasing public. Roofing materials have been devised for concealing the fastening nails, examples of which are disclosed in U.S. Pat. No. 1,596,272, of G. M. Jordan, US. Pat No. 1,667,185 of W. E. Bartels, and U.S. Pat. No. 855,757 of Crabbs and Pendery.

OBJECTS OF THE INVENTION It is the principal object of the present invention to provide a new and improved shingle unit which presents a thick and windproof butt or shadow line.

It is another object of the present invention to provide a double thickness shingle unit which presents a butt or shadow that is of a thickness presenting a desired improved appearance to the roof.

It is further object of the present invention to provide a covering for roofs and the like which embodies a plurality of overlapping composite shingle units which are positively interconnected and defining windproof butt lines of double thickness so as to create an attractive and desirable appearance.

It is another object of the present invention to provide a composition shingle unit which can be laid in horizontal courses having a selected exposure area between butt lines of adjacent courses thereby allowing variations in aesthetic appearance.

It is still another object of the present invention to provide a method of covering a surface with a roof covering of the above character in which horizontally adjacent shingle units may be positioned in overlapping interconnected relationship with each successive horizontal row laid in overlapping relationship with the previously laid row and connected thereto in a manner such that each shingle unit is fastened to the underlying substructure with hidden fasteners.

Othe objects, advantages and capabilities of the present invention will become more apparent as the de scription proceeds taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION The shingle unit of the present invention is of double thickness to present a thick butt line and has been designed so that the butt line of each shingle unit is completely wind resistant. The design is also such that the shingle units can be quickly and easily laid in overlapping horizontal courses or rows with each shingle unit within a course overlapping the adjacent shingle unit in the course to establish a durable unified covering for large surfaces such as the side walls or roofs of building structures.

Each shingle unit includes an over and under sheet, preferably of rectangular configuration, which are hingedly connected along a common longitudinal edge for movement between a face-to-face abutting position and an edge-to-edge, extended co-planar position. The sheets are also longitudinally displaced or offset to define an overlapping portion of the over sheet and an extension portion of the under sheet. With this construc tion, the sheets can be placed in their extended position upon the underlying surface to which the shingle units are to be laid, and fasteners, preferably in the form of roofing nails or the like, driven through the under sheet along its hinged connection to the over sheet to positively position and secure the shingle unit to the underlying surface. The over sheet can then be swung about its hinged connection to the under sheet so as to be positioned in its abutting face-to-face position relative to the under sheet to thereby cover the nail fasteners for aesthetic purposes.

In laying a course or horizontal row of the shingle units, each shingle unit in the course is fastened to the surface in longitudinally aligned relationship with the overlapping portion of each newly added shingle unit overlying the extension portion of the previously laid shingle unit so that adjacent shingle units are interconnected. Successive courses or horizontal rows of shingle units are laid similary to the first row and in an overlapping relationship with the upper edge of the first row so that each row is also overlapped and positively interconnected.

The hinged connection of the over and under sheets is preferably made with an asphalt impregnated fabric strip which is readily flexible and which is bonded to the connected commmon edges of the over and under sheets so that the sheets are freely movable between the aforementioned positions. Additionally, a spacer strip may be positioned between the over and under sheets along their connected edges when the sheets are in their face-to-face abutting position so as to thicken the butt line for aesthetic purposes. The shingle units are also provided with pre-formed tabs and notches which facilitate alignment and desired spacing of the oversheets of each adjacent shingle unit in a horizontal row' so that gaps between horizontally adjacent over sheets are visible to visually separate the horizontally adjacent shingle units.

When the shingle units have been laid in overlapping horizontal rows, the entire assemblage of shingle units arefinterconnected so as to present thick, windproof butt lines for desirable aesthetic purposes and so as to comprise a unified surface covering of interconnected mutually reinforcing shingle units which will withstand years of outside exposure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a building structure with the roof thereof being covered with the interconnected shingle units of the present invention;

FIGS. 2 through 4 are enlarged perspective operational views illustrating the manner in which the shingle units of the present invention are affixed to a substructure.

FIG. 5 is a further enlarged vertical section taken along line 55 of FIG. 2;

FIG. 6 is a still further enlarged fragmentary vertical section similar to FIG. 5;

FIG. 7 is an enlarged fragmentary vertical section of the same scale as FIG. 6 with the over and under sheets of the shingle unit in their positions shown in FIG. 4',

FIG. 8 is a top plan view of the shingle unit of the present invention in the position shown in FIG. 2;

FIG. 9 is a fragmentary perspective view illustrating the interconnection of the shingle units in a surface covering system;

FIG. 10 is a view similar to FIG. 9 further illustrating the interrconnection of the shingle units in a surface covering system;

FIG. 11 is an enlarged side elevation illustrating the connection of overlapping rows of shingle units to the subsurface structure,

FIG. 12 is a further enlarged fragmentary vertical section showing the connection of overlapping rows of shingle units to the subsurface structure;

FIGS. 13 through 15 are operational views similar to FIGS. 2 through 4 illustrating the connection of a second embodiment of the shingle unit of the present invention to a substructure;

FIG. 16 is an enlarged vertical section taken along line 16-16 of FIG. 13;

FIG. 17 is an enlarged fragmentary vertical section showing the hinged connection of the over and under sheets of the shingle unit shown in FIG. 16; and

FIG. 18 is an enlarged fragmentary vertical section showing the hinged connection of the over and under sheets of the second embodiment of the shingle unit of the present invention as the sheets are positioned in FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, a plurality of the shingle units 10 of the present invention are shown laid in horizontal overlapping courses or rows and affixed to the underlying substructure of the roof of a house 12. As best seen in FIGS. 2 through 8, each shingle unit 10 is comprised of a rectangular under sheet 14 and a substantially rectangular over sheet 16 which are, in the preferred form, composed of asphalt sheets impregnated on one surface with a granular grit material so that one surface of each sheet is roughened and the opposite surface is relatively smooth. The over and under sheets, 16 and 14, respectively, are hingedly connected in longitudinally offset relationship by a strip 18 of asphalt impregnated fabric material which is bonded along the bottom edge of both the over and under sheets when they are in an abutting face-to-face position as illustrated in FIG. 4. The hinged strip 18, of course, is conveniently affixed to the over and under sheets by laying them in an extended co-planar edge-toedge position, as illustrated in FIG. 2, so that the hinge strip overlies the adjacent bottom edges of each sheet on the relatively smooth surface of each sheet. It is important to appreciate at the outset that the asphalt impregnated fabric strip 18 will adhere upon contact with the relatively smooth face of the over and under sheets but for a secure bond to the roughened surface of an asphalt sheet, an additional layer of liquid asphalt should be applied to the roughened surface prior to bonding the hinge strip to the asphalt sheet. For a purpose to be described more clearly later, a spacer strip 20, preferably made from the. same asphalt material as the over and under sheets is bonded to the fabric hinge 18 along the bottom edge of the over sheet with the roughened face of the spacer strip lying in abutting relationship with the fabric hinge. As mentioned previously, to obtain a desired bond, it is preferable that a layer of liquid asphalt be applied to the roughened surface of the spacer strip 20 before bonding it to the hinge strip 18 to assure a strong bond.

It will be appreciated that the over sheet 16 is offset longitudinally of the under sheet 14 and thereby defines an overhang portion 22 of the over sheet and an extension portion 24 or the under sheet. Furthermore, the over sheet 16 has a tab 26 on one side edge adjacent the upper edge of the sheet which protrudes longitudinally away from the end opposite the overhang portion 22 of the over sheet a predetermined distance for a reason to be explained later. A notch 28 is cut in the bottom edge of the under sheet 14 in transverse alignment with extension tab 24, the notch being approximately the same as the width of the tab 26 so that the tab and the notch will serve to properly align and space horizontally adjacent shingle units in the roofing assemblage as will be explained later. It should be noted that the over sheet 16 is slightly narrower than the under sheet 14 whereby the upper edge of the under sheet extends beyond the upper edge of the over sheet and, as will become more clear with the description hereinafter, this arrangement minimizes ripples in the roof which could otherwise be created. Also, it is important to note that the asphalt impregnated hinge strip is exposed along the bottom edge of the extension portion 24 of the under sheet.

Referring again to FIGS. 2 through 4, the shingle units 10 are affixed to the substructure of the roof by unfolding the first shingle unit to be affixed so that the over and under sheets thereof are in the extended coplanar position illlustrated in FIG. 2, and then driving fasteners 30 such as roofing nails, through the hinged strip 18 at the bottom edge of the under sheet 14 so that the, fasteners 30 will become embedded in the substructure and thereby positivlely position and fasten the shingle unit tothe substructure. Next, the over sheet 16 is swung as illustrated in FIGS. 3 and 4, into overlying face-to-face relationship with the under sheet 14 and in a position whereby the next horizontally adjacent shingle unit can be properly positioned and secured in place.

Refering now to FIGS. 9 and 10, the next horizontally adjacent shingle unit is positioned so that the overhang portion 22 of the over sheet 16 overlies the extension portion 24 of the under sheet 14 of the previously laid shingle unit with the outermost edge of the overhang portion in abutment with the tab 26 on the previously laid shingle unit. Bylining this edge with the notch 28 in the under sheet of the previously laid UIIILHII exposed gap is defined between the over sheets 16 of the adjacent units. It will be appreciated, when the units are so positioned, that the under sheets 14 are abutted in edge-to-edge relationship establishing a continuous base for the over sheets and the overhang portion 22 of one unit will engage in face-to-face relationship the extension portion 24 of the adjacent unit whereby the asphalt impregnated hinge strip 18 on the extension portion will automatically bond itself on a warm day to the relatively smooth face of the overhang portion of the one unit thereby interconnecting the overhang and extension portions of the adjacent units. Next, the over sheet 16 of the shingle unit now being attached is pivoted into its extended position, FIG. 8, and fasteners 30 are driven through the hinge strip 18 at the lower edge of the under sheet to fasten the second shingle unit to the substructure. The over sheet of the second unit is thereafter pivoted back into its face-to-face relationship with the under sheet. Successive shingle units are fastened to the substructure in this manner until a horizontal course or row of the shingle units has been laid.

The next horizontal row of shingle units is laid in the same manner and each unit is positioned to overlie the previously laid row a predetermined amount. This amount of overlap is governed by the length of the tab 26 on the over sheets whereby the shingle units in the next row being laid can be positioned so that the bottom hinged edges of the over and under sheets lie in a horizontal line including the bottom edge of the tab. Also, preferably each shingle unit is positioned relative to the shingle unit in the previously laid row so that it overlaps two shingle units in that row and the extent to which it overlaps the respective shingle units can be varied to vary pattern of the completed roof covering.

The relationship of the shingle unit in each successive row of units is best illustrated in FIGS. 11 and 12 wherein it can be seen that the nail fasteners 30 extend not only through the hinge strip 18 at the lower edge of the under sheet 14 of each shingle unit but also through the upper edges of the shingle unit in the preceding row so that each nail fastener anchors the bottom edge of each shingle unit and the top edges of the shingle unit in the previously laid row. It should be appreciated that by fastening the shingle units in this manner, that the butt line or bottom edge of each shingle unit is fastened to the substructure to prevent the wind from lifting the bottom edge of the shingle units and thereby damaging the roof structure. Also, since the over sheet 16 is positioned to overlie the nail fasteners 30, they are hidden from view presenting an aesthetically pleasing roof covering.

It will be appreciated that the aforedescribed shingle units are of double thickness, with the exception of the gaps between adjacent over sheets, so that the entire roof covering is substantially of double thickness giving a relatively heavy or bulky appearance. Furthermore, by utilizing the spacer strip 20 along the hinged connection of the over and under sheets, the thickness of the shingle units along the butt line is triple thickness and using conventional composite roofing material, this butt line can approximate it of an inch in thickness thereabove and be affixed to the substructure by the fasteners in the second row thereabove. This would establish a long lasting roof covering of triple thickness' A completed roof covering can be seen to consist of a plurality of the previously described shingle units laid in overlapping horizontal rows with the shingle units in each row overlapping adjacent shingle units so as to establish a totally unified, self-reinforcing assemblage which is both water-repellent and wind resistant. Also, due to the design of the shingle units, each row of shingle units and each shingle unit in a row is uniformly spaced to present a neat attractive roof covering. It will be appreciated from the foregoing description that the roof covering made from the shingle unit is very quickly and easily laid since the units are designed to be self-aligned and spaced during assemblage.

A second embodiment of the shingle unit of the present invention isshown in FIGS. 13 through 18 with like parts having been given like reference numerals with a prime suffix. In this embodiment, a substantially rectangular over sheet 16' is again hingedly connected to a rectangular under sheet 14 by a strip 18' of asphalt impregnated fabric connecting the over and under sheets along their bottom edges so that the roughened surfaces of the over and under sheets are both directed upwardly when the sheets are in their face-to-face relationship illustrated in FIG. 15. Again, when affixing the hinge strip 18 to the over and under sheets, a layer of liquid asphalt is preferably spread along the lower edge of the under sheet so that the strip will be suitably bonded to the rough upper surface of the under sheet. In this embodiment of the invention, the spacer strip 20' is not bonded to the hinge strip 18 along the bottom edge of the over sheet 16' but rather is releasably bonded to the hinge strip along the uppermost edge of the under sheet 14' so that it will remain affixed to the shingle unit 10 while the shingles are being placed in position on the substructure of the roof but can be torn or released from the hinge and placed in the position illustrated in FIG. 15. Preferably, when the spacer strip 20' is positioned as shown in FIG. 13, the roughened surface is directed upwardly so that the spacer strip can merely be pivotally swung, FIG. 14, into the position shown in FIG. 15 thereby separating the spacer strip from the hinge strip 18' and positioning the spacer strip in face-to-face abutting relationship with the hinge strip and with the roughened surface of the spacer strip directed downwardly. This orientation of the spacer strip is preferable since a good bond between the spacer and hinge strips when they are in the position of FIG. 13, with the smooth surface of the strip being bonded to the hinge strip, is more important than a good bond when the spacer and hinge strips are in the position of FIG. 15 since the nail fasteners 30' will be driven through the spacer strip and the hinge strip after they have been positioned as in FIG. 15 to secure the shingle unit to the substructure and in so doing positively position the spacer strip relative to the hinge strip.

The shingle units of the second embodiment would be connected as with the shingle units of the first described embodiment to form a unified roof structure with shingle units not only overlapping in each horizontal row, but with each successive horizontal row overlapping the previously laid row.

It will be appreciated that along the gaps between adjaceht over sheets a horizontal row that the roof covering is single rather than double thickness. Accordingly, it is contemplated that the life of each shingle unit and the composite roof covering could be extended by adding an additional layer of asbestos, foil, asphalt composite or the like on top of the under sheet to establish a double thickness in the gaps and a triple thickness throughout the remainder of the roof covermg.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example and that changes in details of structure may be made without departing from the spirit thereof.

What is claimed is:

l. A shingle unit adapted to be laid with other like shingle units in establishing a surface covering system comprising:

a generally rectangular under sheet having a bottom edge;

a generally rectangular over sheet selectively positionable in face-to-face relationship with the under sheet and having a bottom edge in substantial alignment with the bottom edge of said under sheet, said over sheet being offset along its length relative to said under sheet to define an overhang portion of the over sheet;

the end of said sheet opposite from the overhang portion thereof having a tab portion extending away therefrom against which the overhang portion of an adjacent shingle can abut to establish an exposed gap between over sheets of adjacent shingle units;

hinge means formed by a strip of cloth material impregnated with an asphalt tar material bonded to said over and under sheets adjacent the bottom edges thereof connecting said under sheet to said over sheet along said bottom edges thereof whereby a course of said shingle units can be laid in overlapping relationship with a portion of the under sheet of one shingle unit lying beneath the overhang portion of the over sheet of an adjacent shingle unit; and

an elongated spacer strip releasably connected along an edge thereof to the under sheet at a location spaced from the bottom edge of the under sheet and adapted to be removed from the under sheet and secured in a position along and adjacent to the bottom edge of the under sheet between the under sheet and the over sheet to increase the thickness of said hinged connection therebetween.

2. The shingle unit of claim 1 further including a notch in the bottom edge of said under sheet in substantial alignment with the tab portion of the over sheet.

3. The shingle unit of claim 1, wherein said tar impregnated strip of cloth material extends along said under sheet beyond the end of said over sheet which has the tab portion thereon to define a hat sealing connection portion along which the overhang portion of the over sheet of an adjacent shingle unit can be connected to the under sheet.

4. The shingle unit of claim 1 wherein said spacer strip has a roughened surface and a relatively smooth surface and wherein said relatively smooth surface is in face-to-face relationship with the under sheet when the spacer strip is positioned along the bottom edge of the under sheet.

5. A surface covering system adapted to be secured to a support surface, comprised of a plurality of shingle units as defined in claim 1 said shingle units being disposed in overlapping courses with each course having aligned shingle units whereby the overhang portion of one unit is positioned in face-to-face relationship with the extension portion of an adjacent unit, and the bottom edges of the shingle unit in each course overlying an upper edge of the shingle units in an adjacent course of shingle units.

6. The surface covering system of claim 5, wherein the over sheet of each shingle unit in a course of shingle units are spaced to define exposed gaps therebetween.

7. The surface covering system of claim 6, wherein the shingle units in each course are staggered relative to the shingle units in an adjacent course so that each shingle unit in one course overlaps a pair of shingle units in an adjacent course.

8. The surface covering system of claim 7 wherein said shingle units are each secured to said surface by fasteners passing through the under sheet adjacent its bottom edge and through the underlying overlapped shingle unit adjacent the upper edge of the overlapped shingle unit.

9. A method of covering a surface with a plurality of shingle units as defined in claim 1 comprising the steps of:

placing a first shingle unit on said surface so that the under and over sheets are in the extended position, positioning the elongated spacer strip adjacent the bottom edge of the under sheet,

fastening the bottom edge of the under sheet and spacer strip of the first shingle unit to the surface, pivotally moving the over sheet into its face-to-face position relative to the under sheet, placing a second shingle unit adjacent to said first shingle unit so that the bottom edges of the under sheets are in alignment and so that when the under and over sheets of the second unit are in face-toface relationship, the over sheet of the second unit overlies the extension portion of the first unit and is slightly spaced form the adjacent end of the over sheet of the first unit to define a gap therebetween,

positioning the elongated spacer strip of the second shingle unit adjacent the bottom edge thereof,

fastening the bottom edge of the under sheet and spacer strip of the second shingle unit to the surface,

successively placing the fastening additional shingle units as with the second shingle unit until an entire row of shingle units have been fastened to the surface, and

successively placing and fastening additional rows of shingle units as with the first row, with each successive row having the bottom edges of the over and under sheets of the units therein overlying the upper edges of the units in the previously laid row until the desired portion of the surface is covered by the shingle units.

10. The method of claim 9 wherein each of said successive rows of shingle units are fastened to said surface by driving fasteners through the bottom edge of the under sheet of the units in that row as well as the upper edges of the shingle units in the next preceding row as the fasteners are driven into said surface.

11. The method of claim 10 further including the step of positioning each of said shingle units in the successive rows so as to overlie a pair of adjacent shingle units in the next preceding row.

i t i II 

1. A shingle unit adapted to be laid with other like shingle units in establishing a surface covering system comprising: a generally rectangular under sheet having a bottom edge; a generally rectangular over sheet selectively positionable in face-to-face relationship with the under sheet and having a bottom edge in substantial alignment with the bottom edge of said under sheet, said over sheet being offset along its length relative to said under sheet to define an overhang portion of the over sheet; the end of said sheet opposite from the overhang portion thereof having a tab portion extending away therefrom against which the overhang portion of an adjacent shingle can abut to establish an exposed gap between over sheets of adjacent shingle units; hinge means formed by a strip of cloth material impregnated with an asphalt tar material bonded to said over and under sheets adjacent the bottom edgEs thereof connecting said under sheet to said over sheet along said bottom edges thereof whereby a course of said shingle units can be laid in overlapping relationship with a portion of the under sheet of one shingle unit lying beneath the overhang portion of the over sheet of an adjacent shingle unit; and an elongated spacer strip releasably connected along an edge thereof to the under sheet at a location spaced from the bottom edge of the under sheet and adapted to be removed from the under sheet and secured in a position along and adjacent to the bottom edge of the under sheet between the under sheet and the over sheet to increase the thickness of said hinged connection therebetween.
 2. The shingle unit of claim 1 further including a notch in the bottom edge of said under sheet in substantial alignment with the tab portion of the over sheet.
 3. The shingle unit of claim 1, wherein said tar impregnated strip of cloth material extends along said under sheet beyond the end of said over sheet which has the tab portion thereon to define a hat sealing connection portion along which the overhang portion of the over sheet of an adjacent shingle unit can be connected to the under sheet.
 4. The shingle unit of claim 1 wherein said spacer strip has a roughened surface and a relatively smooth surface and wherein said relatively smooth surface is in face-to-face relationship with the under sheet when the spacer strip is positioned along the bottom edge of the under sheet.
 5. A surface covering system adapted to be secured to a support surface, comprised of a plurality of shingle units as defined in claim 1 said shingle units being disposed in overlapping courses with each course having aligned shingle units whereby the overhang portion of one unit is positioned in face-to-face relationship with the extension portion of an adjacent unit, and the bottom edges of the shingle unit in each course overlying an upper edge of the shingle units in an adjacent course of shingle units.
 6. The surface covering system of claim 5, wherein the over sheet of each shingle unit in a course of shingle units are spaced to define exposed gaps therebetween.
 7. The surface covering system of claim 6, wherein the shingle units in each course are staggered relative to the shingle units in an adjacent course so that each shingle unit in one course overlaps a pair of shingle units in an adjacent course.
 8. The surface covering system of claim 7 wherein said shingle units are each secured to said surface by fasteners passing through the under sheet adjacent its bottom edge and through the underlying overlapped shingle unit adjacent the upper edge of the overlapped shingle unit.
 9. A method of covering a surface with a plurality of shingle units as defined in claim 1 comprising the steps of: placing a first shingle unit on said surface so that the under and over sheets are in the extended position, positioning the elongated spacer strip adjacent the bottom edge of the under sheet, fastening the bottom edge of the under sheet and spacer strip of the first shingle unit to the surface, pivotally moving the over sheet into its face-to-face position relative to the under sheet, placing a second shingle unit adjacent to said first shingle unit so that the bottom edges of the under sheets are in alignment and so that when the under and over sheets of the second unit are in face-to-face relationship, the over sheet of the second unit overlies the extension portion of the first unit and is slightly spaced form the adjacent end of the over sheet of the first unit to define a gap therebetween, positioning the elongated spacer strip of the second shingle unit adjacent the bottom edge thereof, fastening the bottom edge of the under sheet and spacer strip of the second shingle unit to the surface, successively placing the fastening additional shingle units as with the second shingle unit until an entire row of shingle units have been fastened to the sUrface, and successively placing and fastening additional rows of shingle units as with the first row, with each successive row having the bottom edges of the over and under sheets of the units therein overlying the upper edges of the units in the previously laid row until the desired portion of the surface is covered by the shingle units.
 10. The method of claim 9 wherein each of said successive rows of shingle units are fastened to said surface by driving fasteners through the bottom edge of the under sheet of the units in that row as well as the upper edges of the shingle units in the next preceding row as the fasteners are driven into said surface.
 11. The method of claim 10 further including the step of positioning each of said shingle units in the successive rows so as to overlie a pair of adjacent shingle units in the next preceding row. 